1. Field of the Invention
The present invention relates to an information recording/reproduction apparatus which comprises a shutter opening/closing mechanism on the upper surface of a cartridge holder.
2. Related Background Art
A conventional disk cartridge which stores a recording medium therein has a shutter which is free to open/close. An information recording/reproduction apparatus for performing recording, reproducing, and erasing of information with respect to a recording medium has a shutter opening/closing mechanism. This mechanism opens the shutter of a disk cartridge when the cartridge is inserted in a disk cartridge device, and closes the shutter of the cartridge when the cartridge is ejected from the device.
In particular, as a loading method of a disk cartridge for the information recording/reproduction apparatus, a method of moving a disk cartridge inserted in the device in a direction perpendicular to the disk surface is used. However, in order to meet recent requirements for a low-profile information recording/reproduction apparatus, a method of moving a spindle motor is proposed. In this method, the disk cartridge is not moved in the direction perpendicular to the disk surface, but a spindle motor for moving the disk is moved with respect to the loaded disk.
This method will be explained below using an information recording/reproduction apparatus (a magnetooptical recording/reproduction apparatus) shown in FIGS. 1A to 2B. FIGS. 1A and 2A show a state before a disk cartridge is inserted in a device, and FIGS. 1B and 2B show a state upon completion of loading of the disk cartridge.
A magnetooptical disk 1 is stored in a disk cartridge 2. A shutter 3 is arranged on the disk cartridge 2 to cover the opening portion of the disk cartridge 2 to be free to open/close it. Furthermore, a cartridge holder 4 guides the cartridge 2 inserted in the device to the operation position, and is fixed to a frame. Cam grooves 5 and 6 are formed on the upper surface of the cartridge holder 4, and the two ends of a shutter opening/closing lever 7 are respectively guided along these cam grooves 5 and 6. A guide pin 8, which can engage with the cam groove 5, is formed on one end of the shutter opening/closing lever 7, and a shutter opening/closing pin 9 projects from the other end of the lever 7. The shutter opening/closing pin 9 engages with an end portion 3a of the shutter 3, and is guided along the cam groove 6.
A torsion spring 10 has the following arrangement. One end portion 10b of a coil portion 10a of the spring 10 is supported by the upper surface of the cartridge holder 4, and the other end portion 10c engages with an upright portion 7a of the shutter opening/closing lever 7. For this reason, the shutter opening/closing lever 7 is biased to a position shown in FIG. 1A when no cartridge is inserted. Note that a bias magnet 11 applies a bias magnetic field, and is fixed and supported on the upper surface of the cartridge holder 4.
FIG. 4 is a sectional view of a portion near a shutter opening/closing lever 7. In FIG. 4, a guide pin 18 is constituted by a columnar portion engaging with a cam groove 15 and a flange portion 18a for preventing the guide pin 18 from disengaging from the cam groove 15. A ring-shaped collar 14 is rotatably arranged on a portion, engaging with a cam groove 16, of a shutter opening/closing pin 19. A stop ring 13 prevents the shutter opening/closing pin 19 from disengaging from the cam groove 16. Since the collar 14 arrangement is provided, the frictional force acting between the shutter opening/closing pin 19 and the cam groove 16 is reduced, thus preventing wear.
One end of a pivot plate 21 is supported by the frame to be pivotal about pins (shafts) 42a and 42b. A spindle motor 22 for rotating the disk 1, and alignment pins 27a to 27d for aligning the cartridge 2 are fixed on the pivot plate 21. Note that, in addition, a driving system having a linear motor, an optical head (not shown), and the like are fixed to the frame.
Guide rollers 23a and 23b are pivotally arranged on the side surfaces of the pivot plate 21. A slide cam 24 is arranged to be slidable in a direction parallel to the insertion direction of the cartridge. Cam grooves 25 engaging with the guide rollers 23a and 23b are formed on upright portions of the slide cam 24 to be located at the two sides of the guide rollers 23a and 23b. Each cam groove 25 is defined by a horizontal portion 25a and an inclined portion 25b.
The slide cam 24 has guide grooves 24a and 24b, which slidably engage with guide pins 26a and 26b projecting from the frame. The slide cam 24 is always biased toward a front panel 30 having a cartridge insertion hole 29 by torsion springs 28a and 28b.
A detection lever 35 is supported to be pivotal about a shaft 36 projecting from the frame, and is biased in the direction of an arrow in FIG. 1A by a torsion spring 37. In the state shown in FIG. 1A, a recess portion 35a of the detection lever 35 engages with a lock pin 38 formed on the slide cam 24 and holds the slide cam 24 at a position separated from the front panel 30 against the biasing force of the torsion springs 28a and 28b.
When the cartridge 2 is inserted in the device, an end portion 35b of the detection lever 35 is pushed by the front end of the cartridge 2, and the engaging state between the recess portion 35a and the lock pin 38 is released. For this reason, the slide cam 24 moves toward the front panel side by the biasing force of the torsion springs 28a and 28b.
An eject motor unit 39 is constituted by a rotary disk 40 rotated by the motor, and a pin 41 arranged near the outer periphery of the rotary disk 40. When the cartridge is to be ejected, the pin 41 rotates in the direction of an arrow in FIG. 1A, and pushes a projection 24e, contacting the pin 41, of the slide cam 24, thereby moving the slide cam 24 backward.
An operation upon loading of the cartridge will be described below. FIGS. 1A and 2A show a state before loading of the cartridge 2. When the disk cartridge 2 is inserted into the device from the state shown in FIGS. 1A and 2A, the shutter opening/closing pin 9 of the shutter opening/closing lever 7 contacts the end portion 3a of the shutter 3. When the cartridge 2 is further inserted, the shutter opening/closing lever 7 pivots in the direction of an arrow in FIG. 1A to open the shutter.
When the shutter opening/closing pin 9 of the shutter opening/closing lever 7 is guided to a linear portion 6a of the cam groove 6, the shutter 3 is opened completely, and thereafter, the cartridge 2 is pushed into the device while the shutter 3 is kept open. Immediately before the cartridge 2 reaches a position shown in FIG. 1B, the side surface of the cartridge 2 contacts the end portion 35b of the detection lever 35. When the cartridge is further pushed to the end, the detection lever 35 is rotated in a direction opposite to the direction of the arrow, and the engaging state between the recess portion 35a and the lock pin 38 is released, as shown in FIG. 1B. When this engaging state is released, the slide cam 24 moves to the position illustrated in FIGS. 1B and 2B by the biasing force of the springs 28a and 28b.
Before loading, the guide rollers 23a and 23b of the pivot plate 21 are located in the horizontal portions 25a of the corresponding cam groove 25 of the slide cam 24, and the free end side of the pivot plate 21 is located at the lower position. For this reason, the spindle motor 22, and the alignment pins 27a to 27d do not disturb the insertion of the cartridge 2. Upon movement of the slide cam 24, the guide rollers 23a and 23b are guided along the inclined portion 25b of the cam grooves 25. In this case, the pivot plate 21 is pivoted about the shafts 42a and 42b, and contacts a contact surface 4a of the cartridge holder 4. With this operation, the spindle motor 22 and the alignment pins 27a to 27d move upward, and respectively achieve clamping of the disk and the alignment of the cartridge.
FIG. 5 is a perspective view showing the cartridge 2 with the shutter 3 which is fully opened. The shutter 3 is supported to be slidable in a recess portion 2b of the cartridge 2. Since both a bridge portion 2a of the cartridge 2 and a portion 3b of the shutter 3 are formed to have substantially the same thickness as that of the disk 1, the cartridge 2 will not contact the bias magnet 11 and an optical head (not shown) if the shutter 3 is quickly opened as in this example.
An operation upon ejection of the cartridge is performed as follows. Upon reception of an eject command, the rotary disk 40 of the eject motor unit 39 begins to rotate from the position shown in FIG. 1B in the direction of the arrow, and the pin 41 pulls the slide cam 24 backward against the biasing force of the springs 28a and 28b. Since the guide rollers 23a and 23b, which are located in the inclined portions 25b of the cam grooves 25 of the slide cam 24, are guided to the horizontal portions 25a of the cam grooves 25 upon movement of the slide cam 24, the free end portion side of the pivot plate 21 moves downward, as shown in FIG. 2A. Therefore, the spindle motor 22 and the alignment pins 27a to 27d also move downward, thus allowing ejection of the disk cartridge 2.
In the state shown in FIG. 1B, since the lock pin 38 of the slide cam 24 contacts a linear portion 35c of the detection lever 35, the detection lever 35 cannot be pivoted. However, when the slide cam 24 moves to almost the end, the lock pin 38 is separated from the linear portion 35c, and the detection lever 35 is pivoted in the direction of the arrow by the biasing force of the torsion spring 37. By the pivoting force of the detection lever 35, the cartridge 2 is ejected from the cartridge holder 4. The state shown in FIG. 1A is attained when the pin 41 of the eject motor unit 39 reaches a position A. However, when the eject motor is stopped in this state, the slide cam 24 cannot move forward upon execution of the next loading. For this reason, the eject motor is rotated by half a revolution, and is stopped at a position B using a limit switch (not shown), and the like.
As described above, since the plate on which the spindle motor is attached moves upward/downward upon loading and ejection of the disk cartridge, the device space can be efficiently utilized.
However, in the prior art, as shown in FIG. 4, since the flange portion 18a of the guide pin 18 is arranged at the inner side of the cartridge holder 4, the flange portion 18a contacts the cartridge 2. FIG. 3 shows a state immediately before the shutter of the disk cartridge is almost fully opened upon insertion of the cartridge 2 in the cartridge holder 4. In this state, the flange portion 18a is located immediately above the recess portion (hatched portion) 2b of the cartridge 2. When the cartridge 2 is further pushed, the flange 18a moves along the cam groove 5 and passes an edge 2c of the recess portion 2b. However, since the flange portion 18a slightly projects into the cartridge holder 4, the flange portion 18a passes the edge 2c while climbing over it.
Therefore, when cartridge insertion is repeated, the edge 2c is worn. In some cases, the flange portion 18a may be caught by the edge 2c. If the cartridge is pushed by force into the cartridge holder while caught by the edge 2c, since the force directly acts on the cartridge 2 and the shutter opening/closing lever 7, the cartridge 2 and the shutter opening/closing lever 7 may be damaged (e.g., disengaged due to deformation) if the cartridge is handled carelessly.